In the production of semiconductor devices, electron beam exposure technology is a promising lithography technology that enables exposure of a fine pattern with a width of 0.1 micrometers or smaller. In electron beam exposure apparatuses, an electron optical element is used to control optical characteristics of an electron beam. Electron lenses are classified into an electromagnetic type and an electrostatic type. The structure of an electrostatic electron lens is simpler than that of an electromagnetic electron lens because an electrostatic electron lens does not have a coil core. Therefore, the electrostatic type is advantageous in reduction in size. Regarding the electron beam exposure technology, multi-beam systems, which form a pattern by simultaneously using a plurality of electron beams instead of using a mask, have been proposed. A multi-beam system includes an electron lens array in which electron lenses are arranged one dimensionally or two dimensionally. In the electron beam lithography technology, the limit of microfabrication is not determined by the diffraction limit of an electron beam but by optical aberrations of an electron optical element. Therefore, it is important to realize an electron optical element having small aberrations.
For example, PTL 1 describes a charged particle beam lens array including a plurality of charged particle beam lenses that are arranged two-dimensionally and that are divided into at least two groups having different refractive powers when the same voltage is applied to all lenses.